Final answer:
The base of an exponential function with a growth rate of 7% would be 1.07, since an exponential growth function is written as y = a · b^x, and this base is determined by adding 1 to the percentage growth rate as a decimal.
Step-by-step explanation:
The base of an exponential function that represents a growth rate of 7% would be 1.07. This is because an exponential growth function is typically in the form y = a · bx, where a is the initial amount, b is the base or growth factor, and x is the time. The growth factor b is calculated by adding 1 to the decimal form of the percentage growth rate, thus 7% as a decimal is 0.07, and when we add 1 to it, we get a growth factor or base of 1.07.
For example, if you wanted to calculate the amount after 10 years, you would use the equation y = a · 1.0710. This incorporates the constant growth rate over the 10-year period. According to the rule of 70, a system growing at 7% per year would take approximately 10 years to double in size.